read_dir.c

#include <libgen.h>
#include <minix.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>

int main(int argc, char *argv[]) {
    if (argc != 3) {
        fprintf(stderr, "Usage :\n");
        fprintf(stderr, "\t./%s <image file> <inode n°>\n", basename(argv[0]));
        exit(EXIT_FAILURE);
    }

    struct minix_inode inode = {0};
    int inode_nb = atoi(argv[2]);

    unmarshal_inode(&inode, inode_nb, argv[1]);

    int nb_blocks_used = (inode.i_size / BLOCK_SIZE) + 1;
    if (inode.i_size > BLOCK_SIZE && inode.i_size % BLOCK_SIZE != 0) {
        nb_blocks_used++;
    }

    for (int i = 0; i < nb_blocks_used; i++) {
        ssize_t phys_num = bmap(&inode, argv[1], i);

        if (phys_num == -1) {
            fprintf(stderr, "bmap has failed...\n");
            exit(EXIT_FAILURE);
        }

        char buf[BLOCK_SIZE + 1] = {0};

        if (read_data_block(buf, argv[1], phys_num) == -1) {
            fprintf(stderr, "read_data_block has failed...\n");
            exit(EXIT_FAILURE);
        }

        struct minix_dir_entry dir_entry = {0};
        for (size_t j = 0; j < BLOCK_SIZE / sizeof(struct minix_dir_entry);
             j++) {
            memcpy(&dir_entry, &buf[j * sizeof(struct minix_dir_entry)],
                   sizeof(struct minix_dir_entry));

            if (!S_ISDIR(inode.i_mode)) {
                fprintf(stderr,
                        "Inode isn't associated to a directory, cannot read "
                        "the contents associated with the given inode (n°%d)\n",
                        inode_nb);
                exit(EXIT_FAILURE);
            }

            if (strlen(dir_entry.name) != 0) {
                fprintf(stdout, "Directory entry : %s\t(Inode n°%d)\n",
                        dir_entry.name, dir_entry.inode);
            }
        }
    }

    return EXIT_SUCCESS;
}